1. Budtz-Jörgensen E. Restoration of the partially edentulous mouth--a comparison of overdentures, removable partial dentures, fixed partial dentures and implant treatment. J Dent. 1996; 24:237–244.
2. Chee W, Jivraj S. Treatment planning of the edentulous mandible. Br Dent J. 2006; 201:337–347.
3. van Kampen F, Cune M, van der Bilt A, Bosman F. Retention and postinsertion maintenance of bar-clip, ball and magnet attachments in mandibular implant overdenture treatment: an in vivo comparison after 3 months of function. Clin Oral Implants Res. 2003; 14:720–726.
4. Chaimattayompol N, Arbree NS. Assessing the space limitation inside a complete denture for implant attachments. J Prosthet Dent. 2003; 89:82–85.
5. Cehreli MC, Karasoy D, Kokat AM, Akca K, Eckert SE. Systematic review of prosthetic maintenance requirements for implant-supported overdentures. Int J Oral Maxillofac Implants. 2010; 25:163–180.
6. Cune M, Burgers M, van Kampen F, de Putter C, van der Bilt A. Mandibular overdentures retained by two implants: 10-year results from a crossover clinical trial comparing ball-socket and bar-clip attachments. Int J Prosthodont. 2010; 23:310–317.
7. Krennmair G, Weinländer M, Krainhöfner M, Piehslinger E. Implant-supported mandibular overdentures retained with ball or telescopic crown attachments: a 3-year prospective study. Int J Prosthodont. 2006; 19:164–170.
8. Bilhan H, Geckili O, Sulun T, Bilgin T. A quality-of-life comparison between self-aligning and ball attachment systems for 2-implantretained mandibular overdentures. J Oral Implantol. 2011; 37:167–173.
9. Engelhardt F, Zeman F, Behr M, Hahmel S. Prosthetic complications and maintenance requirements in locator-attached implantsupported overdentures: A retrospective study. Eur J Prosthodont Restor Dent. 2016; 24:31–35.
10. Türk PE, Geckili O, Türk Y, Günay V, Bilgin T. In vitro comparison of the retentive properties of ball and locator attachments for implant overdentures. Int J Oral Maxillofac Implants. 2014; 29:1106–1113.
11. Rutkunas V, Mizutani H, Takahashi H. Influence of attachment wear on retention of mandibular overdenture. J Oral Rehabil. 2007; 34:41–51.
12. Grossmann Y, Nissan J, Levin L. Clinical effectiveness of implantsupported removable partial dentures: a review of the literature and retrospective case evaluation. J Oral Maxillofac Surg. 2009; 67:1941–1946.
13. Osman RB, Payne AG, Ma S. Prosthodontic maintenance of maxillary implant overdentures: a systematic literature review. Int J Prosthodont. 2012; 25:381–391.